1. Field of the Invention
The present invention relates to a signal interface wherein signals transmitted from a plurality of transmitter units are received by a receiver unit.
2. Description of the Related Art
As a technique which heightens the transfer rate of data from a transmitter unit to a receiver unit without increasing the number of data lines, there has been proposed one wherein the values of currents to be fed to the data lines are changed in accordance with multi-level data (in, for example, Japanese Unexamined Patent Application Publication No. 2001-156621 or No. 2002-152029).
Conventionally, in cases where signals were transferred from a plurality of transmitter units to one receiver unit, a signal line needed to be laid for each of the transmitter units, in which case the number of the signal lines became large. Besides, in cases where signals were transmitted by employing a common signal line, arbitration needed to be done to determine the use right of the signal line, to prevent conflict of the signals. Accordingly, a technique in which signals are simultaneously transferred by employing a common signal line has not been proposed yet.